skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: On the Incidence of Wise Infrared Excess Among Solar Analog, Twin, and Sibling Stars

Abstract

This study presents a search for infrared (IR) excess in the 3.4, 4.6, 12, and 22 μ m bands in a sample of 216 targets, composed of solar sibling, twin, and analog stars observed by the Wide-field Infrared Survey Explorer ( WISE ) mission. In general, an IR excess suggests the existence of warm dust around a star. We detected 12 μ m and/or 22 μ m excesses at the 3 σ level of confidence in five solar analog stars, corresponding to a frequency of 4.1% of the entire sample of solar analogs analyzed, and in one out of 29 solar sibling candidates, confirming previous studies. The estimation of the dust properties shows that the sources with IR excesses possess circumstellar material with temperatures that, within the uncertainties, are similar to that of the material found in the asteroid belt in our solar system. No photospheric flux excess was identified at the W1 (3.4 μ m) and W2 (4.6 μ m) WISE bands, indicating that, in the majority of stars of the present sample, no detectable dust is generated. Interestingly, among the 60 solar twin stars analyzed in this work, no WISE photospheric flux excess was detected. However, a null-detectionmore » excess does not necessarily indicate the absence of dust around a star because different causes, including dynamic processes and instrument limitations, can mask its presence.« less

Authors:
; ; ; ;  [1];  [2];  [3]
  1. Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Campus Universitário, Natal, RN, 59072-970 (Brazil)
  2. European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching (Germany)
  3. Departamento de Física, Universidade Federal do Ceará, Caixa Postal 6030, Campus do Pici, 60455-900, Fortaleza, Ceará (Brazil)
Publication Date:
OSTI Identifier:
22661332
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 837; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTEROIDS; DETECTION; DUSTS; INFRARED SURVEYS; SOLAR SYSTEM; STARS

Citation Formats

Da Costa, A. D., Martins, B. L. Canto, Lima Jr, J. E., Silva, D. Freire da, Medeiros, J. R. De, Leão, I. C., and Freitas, D. B. de, E-mail: dgerson@fisica.ufrn.br. On the Incidence of Wise Infrared Excess Among Solar Analog, Twin, and Sibling Stars. United States: N. p., 2017. Web. doi:10.3847/1538-4357/837/1/15.
Da Costa, A. D., Martins, B. L. Canto, Lima Jr, J. E., Silva, D. Freire da, Medeiros, J. R. De, Leão, I. C., & Freitas, D. B. de, E-mail: dgerson@fisica.ufrn.br. On the Incidence of Wise Infrared Excess Among Solar Analog, Twin, and Sibling Stars. United States. doi:10.3847/1538-4357/837/1/15.
Da Costa, A. D., Martins, B. L. Canto, Lima Jr, J. E., Silva, D. Freire da, Medeiros, J. R. De, Leão, I. C., and Freitas, D. B. de, E-mail: dgerson@fisica.ufrn.br. Wed . "On the Incidence of Wise Infrared Excess Among Solar Analog, Twin, and Sibling Stars". United States. doi:10.3847/1538-4357/837/1/15.
@article{osti_22661332,
title = {On the Incidence of Wise Infrared Excess Among Solar Analog, Twin, and Sibling Stars},
author = {Da Costa, A. D. and Martins, B. L. Canto and Lima Jr, J. E. and Silva, D. Freire da and Medeiros, J. R. De and Leão, I. C. and Freitas, D. B. de, E-mail: dgerson@fisica.ufrn.br},
abstractNote = {This study presents a search for infrared (IR) excess in the 3.4, 4.6, 12, and 22 μ m bands in a sample of 216 targets, composed of solar sibling, twin, and analog stars observed by the Wide-field Infrared Survey Explorer ( WISE ) mission. In general, an IR excess suggests the existence of warm dust around a star. We detected 12 μ m and/or 22 μ m excesses at the 3 σ level of confidence in five solar analog stars, corresponding to a frequency of 4.1% of the entire sample of solar analogs analyzed, and in one out of 29 solar sibling candidates, confirming previous studies. The estimation of the dust properties shows that the sources with IR excesses possess circumstellar material with temperatures that, within the uncertainties, are similar to that of the material found in the asteroid belt in our solar system. No photospheric flux excess was identified at the W1 (3.4 μ m) and W2 (4.6 μ m) WISE bands, indicating that, in the majority of stars of the present sample, no detectable dust is generated. Interestingly, among the 60 solar twin stars analyzed in this work, no WISE photospheric flux excess was detected. However, a null-detection excess does not necessarily indicate the absence of dust around a star because different causes, including dynamic processes and instrument limitations, can mask its presence.},
doi = {10.3847/1538-4357/837/1/15},
journal = {Astrophysical Journal},
number = 1,
volume = 837,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 2017},
month = {Wed Mar 01 00:00:00 EST 2017}
}
  • Using the Sloan Digital Sky Survey Data Release 7 (SDSS DR7) spectroscopic catalog, we searched the WISE AllWISE catalog to investigate the occurrence of warm dust, as inferred from IR excesses, around field M dwarfs (dMs). We developed SDSS/WISE color selection criteria to identify 175 dMs (from 70,841) that show IR flux greater than the typical dM photosphere levels at 12 and/or 22 μm, including seven new stars within the Orion OB1 footprint. We characterize the dust populations inferred from each IR excess and investigate the possibility that these excesses could arise from ultracool binary companions by modeling combined spectralmore » energy distributions. Our observed IR fluxes are greater than levels expected from ultracool companions (>3σ). We also estimate that the probability the observed IR excesses are due to chance alignments with extragalactic sources is <0.1%. Using SDSS spectra we measure surface gravity-dependent features (K, Na, and CaH 3) and find <15% of our sample indicates low surface gravities. Examining tracers of youth (Hα, UV fluxes, and Li absorption), we find <3% of our sample appear young, indicating we are observing a population of field stars ≳1 Gyr, likely harboring circumstellar material. We investigate age-dependent properties probed by this sample, studying the disk fraction as a function of Galactic height. The fraction remains small and constant to |Z| ∼ 700 pc and then drops, indicating little to no trend with age. Possible explanations for disks around field dMs include (1) collisions of planetary bodies, (2) tidal disruption of planetary bodies, or (3) failed planet formation.« less
  • In response to reports of an unusually high number of colorectal cancers among employees on a unit devoted to the manufacture of polypropylene, we examined colorectal cancer incidence rates for 335 workers with at least 6 months employment on this unit from 1960 to 1985. Assuming a 10-year latent period, we found a significant 5.6-fold colorectal cancer excess (7 observed/1.26 expected, standardized incidence ratio (SIR) = 5.6, 95% confidence interval (CI) 2.2 to 11.5), concentrated among mechanical (5 observed/0.47 expected, SIR = 10.6, 95% CI 3.4 to 24.7) and process workers (2 observed/0.40 expected, SIR = 5.0, 95% CI 0.6more » to 17.8). No colorectal cancer was found among administrative/office personnel on our study roster. All of the cancers occurred in employees who initially worked on the unit during its first 6 years of operation, and the minimum interval from start of employment to cancer development was 20 years. In addition, the ages of the cancer cases suggested a younger age distribution than would be expected based on general population rates. Since this study was descriptive in nature, we could not evaluate whether the cancer excess was related to occupational exposures, other environmental factors, or the random clustering of cancers in our worker populations (viz, chance). Further studies are currently ongoing to assess occupational and/or personal factors that may be related to this colorectal cancer excess.« less
  • Interstellar dust presents a significant challenge to extending parallax-determined distances of optically observed pulsational variables to larger volumes. Distance ladder work at mid-infrared wavebands, where dust effects are negligible and metallicity correlations are minimized, has been largely focused on few-epoch Cepheid studies. Here we present the first determination of mid-infrared period-luminosity (PL) relations of RR Lyrae stars from phase-resolved imaging using the preliminary data release of the Wide-field Infrared Survey Explorer (WISE). We present a novel statistical framework to predict posterior distances of 76 well observed RR Lyrae that uses the optically constructed prior distance moduli while simultaneously imposing amore » power-law PL relation to WISE-determined mean magnitudes. We find that the absolute magnitude in the bluest WISE filter is M{sub W1} = (- 0.421 {+-} 0.014) - (1.681 {+-} 0.147)log{sub 10}(P/0.50118 day), with no evidence for a correlation with metallicity. Combining the results from the three bluest WISE filters, we find that a typical star in our sample has a distance measurement uncertainty of 0.97% (statistical) plus 1.17% (systematic). We do not fundamentalize the periods of RRc stars to improve their fit to the relations. Taking the Hipparcos-derived mean V-band magnitudes, we use the distance posteriors to determine a new optical metallicity-luminosity relation. The results of this analysis will soon be tested by Hubble Space Telescope parallax measurements and, eventually, with the GAIA astrometric mission.« less
  • The correlation of spectral line strength with temperature subclass has been examined in a survey of 40 carbon stars at a dispersion of 15 A/mm. The two goals of this search were: (1) to determine if additional cool N-type stars can be added to the list of N stars not having enhanced s-process elements; and (2) to confirm the anticorrelation of s-process enhancements with C-13 enhancement. Among the program stars one normal carbon star was found to have no, or only minor, enhancement of heavy elements associated with the s-process. The suspicion that increased surface C-13 is accompanied by weakmore » line strengths of s-process elements is strongly confirmed. 52 references.« less